A processor, represented by a general-purpose microprocessor, a microcomputer or a DSP, can process data according to an operation program. A DSP is a processor which is specialized in digital signal processing. For example, the operation of a mobile communication terminal device is roughly divided into digital signal processings such as speech encoding/decoding, and modulation/demodulation and a communication protocol processing. Because of the property of the digital signal processing, the former is suitably realized by special-purpose hardware or a programmable DSP. Meanwhile, the latter communication protocol processing is so complicated that it is more suitably realized by software using a high-level language such as the C language. Based on this fact, there has been proposed a method in which the speech encoding/decoding, the channel encoding/decoding, and the modulating/demodulating of the base band processings of a mobile communication terminal device are realized by a DSP whereas the communication protocol processing is realized by a general-purpose microprocessor.
At present, many mobile communication terminal devices are so constructed as to include two processors, i.e., a DSP and a general-purpose microprocessor, as has been described hereinbefore. Meanwhile, a processor (hereinafter referred to also as an integrated processor), in which a DSP and a general-purpose microprocessor are integrated, has been manufactured to realize a mobile communication terminal device. Such an integrated processor is represented by the product SH-DSP (SH7410) made by Hitachi Ltd. This integrated processor can execute an operation while performing the read of a program and the transfer of two data simultaneously, so that it is suitable for digital signal processings such as speech encoding/decoding, channel encoding/decoding and waveform equalization.
Even when a DSP, a general-purpose microprocessor and an integrated processor are employed, however, the digital signal processings such as speed encoding/decoding, channel encoding/decoding and waveform equalization are realized as the processings depending exclusively upon the software over the DSP or the integrated processor. The contents of the processings depending exclusively upon the software vary according to the contents of the operation program but are not expected to cope with the high speed operation sufficiently as the quantity of processings increases. For example, the construction of a mobile communication terminal device is mainly for realizing existing speech communication service. Fast data service is expected to become the main stay in the mobile communication systems of the next generation. For fast data service, more data has to be transmitted than that of the existing case of only speech transmission. Thus, as the signal processing increase in proportion to the amount of transmission this imposes a heavy burden on the mobile communication terminal device. This signal processing includes waveform equalization and channel decoding. In the existing speech transmission service, such processing is performed by software with a programmable processor such as a DSP mounted in a terminal device. However, the processing ability of the processor is not sufficient for coping with fast data service expected to be required of the next generation mobile communication terminal devices.